A few arguments for biodiversity

This is a great video on the connections between human health and biodiversity. Aside from the much-cited utility of rare species as sources for current and future medical compounds, the presenter gives another good example of how biodiversity helps us: he describes the case of vultures in India, whose numbers have drastically dropped due to the use of a cattle medicine that is toxic to the vultures when they feast on the occasional dead cow in the field. Fewer vultures to clean up carrion has led to an explosion in the feral dog population, that has taken over the carrion-eating duties. And more feral dogs means more rabies--an increase of 50000 rabies cases a year in India due to the reduction in vulture population, by the presenter's account.

Sustaining Life, How Human Health Depends on Biodiversity from Robert Moran on Vimeo.

This talk of the value to humans of biodiversity of course makes me think about crop diversity, which is the range of crop species planted in the world, and the abundance of distinct varieties of each crop. Especially here where I live in the Andes mountains, we have a lot of indigenous crops well-suited to our climate. However, changing cultural values, consumption patterns, and climate trends have lessened the use of many of these rare crops, and some are even threatened with extinction. Some might argue that if people choose not to plant or consume these crops, then it must be because they aren't as good as other crops. This may or not be true, but either way it's a very shortsighted vision, because what if maka or ulluco or any one of our many native crop species have some undiscovered use that will be very valuable in the future? For instance cubio (Tropaeolum tuberosum) has already been shown to contain many anti-aphrodisiac chemicals. It was even used by the Incas to feed army troops on long campaigns, so they wouldn't rape and pillage. What if we find that this crop can yield a potent medicine to treat aggression caused by high testosterone levels? Or if it also has anti-cancer properties? It would be good if the crop were still around to use, because otherwise we'd miss out on these and untold other future possibilities.

I have been writing fact sheets about ten species of native Andean crops for an educational garden I'm planning with the local museum here in my town. I just finished the sheet for achira (Canna indica). This plant is probably better known to my US readers as Canna, a showy garden flower:



But achira was originally domesticated by Andean peoples at the very dawn of agriculture as a tuber crop:



It was replaced over time by other crops that had attractive features like a higher yield or less fiber in the tuber, but it is still used to make cookies and for certain special occasions. These uses are diminishing here in the Andes as our diet is more and more dominated by rice and potatoes. But in Vietnam the achira has become a very important plant. Vietnamese farmers grow this tuber and extract its starch through simple methods. The starch is then used to fabricate glass noodles, which are an important food item in Vietnam (also with ceremonial significance) that people used to make from mung bean starch. So in Vietnam there are thousands of acres planted to achira, and it is an important source of income and cottage industry in many regions. However, if achira had disappeared in its native Andean habitat before being introduced to Vietnam, this wonderful and important use of the plant would never have been discovered, and the world would be poorer for it.